endocrine glands hypothalamus pineal gland
TRANSCRIPT
![Page 1: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/1.jpg)
Endocrine Glands
Hypothalamus
Pineal gland
Pituitary gland
Thyroid glandParathyroid glands
Adrenal glands
Pancreas
Ovary(female)
Testis(male)
![Page 2: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/2.jpg)
Chemical Classification of Hormones
Amine hormones are derived from tyrosine or tryptophan Include NE, Epi, thyroxine, melatonin
Polypeptide/protein hormones are chains of amino acids Include ADH, GH, insulin, oxytocin, glucagon,
ACTH, PTH Glycoproteins include LH, FSH, TSH
Steroids are lipids derived from cholesterol Include testosterone, estrogen, progesterone &
cortisol
![Page 3: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/3.jpg)
Water Solubility
Polar water soluble. Cannot pass through cell
membrane Polypeptides, glycoproteins, most amines
Nonpolar (lipophilic) Insoluble in water but soluble in lipid Can pass through cell membrane Steroids and thyroid hormone
![Page 4: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/4.jpg)
Common Aspects of Neural & Endocrine Regulation
Target cells with receptor proteins that combine with the regulatory molecule
The binding causes a specific sequence of changes in target cell (Signal transduction leads to response)
There exists mechanisms to quickly turn off the action of the regulator rapid removal or chemical inactivation There is an OFF switch as well as an ON switch
![Page 5: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/5.jpg)
Mechanisms of Hormone Action
![Page 6: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/6.jpg)
Lipophilic hormones
Pass through cell membrane
Bind to intracellular receptors
The hormone-receptor complex acts as a “Transcription factor”. It activates a gene to make an mRNA from which an enzyme protein is made. This enzyme will in some way change the metabolism of the target cell.
![Page 7: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/7.jpg)
Hormones That Bind to Nuclear Receptor Proteins
Lipid hormones travel in blood attached to carrier proteins They dissociate
from carriers to pass thru plasma membrane of target
Receptors are located in the cytoplasm or nucleus
![Page 8: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/8.jpg)
Polar hormones
Water soluble hormones use cell surface receptors because cannot pass through plasma membrane Actions are mediated by 2nd messengers Hormone is extracellular signal; 2nd messenger
carries signal from receptor to inside of cell Some second messengers include:
cAMP Phospholipase C Tyrosine kinase Calcium ions
![Page 9: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/9.jpg)
Mediates effects of many polypeptide & glycoprotein hormones
Hormone binds to receptor causing dissociation of a G-protein subunit
Adenylate Cyclase-cAMP
![Page 10: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/10.jpg)
Hypothalamus
![Page 11: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/11.jpg)
Hypothalamus
Hypothalamus produces ADH and Oxytocin that are transported to the posterior pituitary for release. (more on these later)
Controls the pituitary gland via a variety of releasing and inhibiting factors. TRH thyrotropin releasing hormone GHRH growth hormone releasing hormone CRH corticotropin releasing hormone Prolactin inhibiting hormone Etc. etc.
![Page 12: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/12.jpg)
Pituitary Gland
![Page 13: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/13.jpg)
Pituitary Gland Pituitary gland is located beneath hypothalamus
![Page 14: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/14.jpg)
Posterior Pituitary
Stores & releases 2 hormones produced in hypothalamus: Antidiuretic hormone
(ADH/vasopressin) which promotes H20 conservation by kidneys
Oxytocin which stimulates contractions of uterus during parturition & contractions of mammary gland alveoli for milk-ejection reflex
Hypothalamus
Neurosecretorycells of thehypothalamus
Axon
Anteriorpituitary
Posteriorpituitary
HORMONE ADH Oxytocin
TARGET Kidney tubules Mammary glands,uterine muscles
![Page 15: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/15.jpg)
Anterior Pituitary
Secretes 6 trophic hormones that maintain size of targets High blood levels
cause target to hypertrophy
Low levels cause atrophy
![Page 16: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/16.jpg)
Anterior Pituitary
Growth hormone (GH) promotes growth, protein synthesis, & movement of amino acids into cells
Thyroid stimulating hormone (TSH) stimulates thyroid to produce & secrete T4 & T3
Adrenocorticotrophic hormone (ACTH) stimulates adrenal cortex to secrete cortisol, aldosterone
![Page 17: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/17.jpg)
Anterior Pituitary
Follicle stimulating hormone (FSH) stimulates growth of ovarian follicles & sperm production
Luteinizing hormone (LH) causes ovulation & secretion of testosterone in testes
Prolactin (PRL) stimulates milk production by mammary glands
![Page 18: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/18.jpg)
Anterior Pituitary
Other hormones/products of the pituitary gland include: MSH - influences skin pigmentation in some
vertebrates and fat metabolism in mammals Endorphins - inhibit the sensation of pain
![Page 19: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/19.jpg)
Pituitary Regulation
Release of A. Pit. hormones is controlled by 1. Hypothalamic releasing & inhibiting factors
2. Feedback from levels of target gland hormones
3. Higher brain centers (via the hypothalamus)
![Page 20: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/20.jpg)
Anterior Pituitary continued
Releasing & inhibiting hormones from hypothalamus are released from axon endings into capillary bed in median eminence Carried by
hypothalamo-hypophyseal portal system directly to another capillary bed in A. Pit.
Diffuse into A. Pit. & regulate secretion of its hormones
![Page 21: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/21.jpg)
Feedback Control of Anterior Pituitary
Target glands produce hormones that feedback to regulate the anterior pituitary and the hypothalamus
![Page 22: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/22.jpg)
Higher Brain Function & Anterior Pituitary Secretion
Hypothalamus receives input from higher brain centers that can affect Pituitary secretion E.g. psychological stress affects circadian
rhythms, menstrual cycle, & adrenal hormones
![Page 23: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/23.jpg)
Adrenal Gland
![Page 24: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/24.jpg)
Adrenal Glands
Sit on top of kidneys
outer cortex inner medulla
![Page 25: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/25.jpg)
Adrenal Glands
Adrenal Cortex Mineralocorticoids
Aldosterone which stimulate kidneys to reabsorb Na+ and secrete K
Glucocorticoids Cortisol which inhibits glucose utilization & stimulates
gluconeogenesis. Inhibits inflammation, Supresses the immune system
![Page 26: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/26.jpg)
Adrenal Medulla
Secretes Epinephrine and Norepinephrine
"fight or flight" response causes:
Increased respiratory rate Increased HR & cardiac output General vasoconstriction which increases venous return Glycogenolysis & lipolysis Etc, etc, etc
![Page 27: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/27.jpg)
Stress
![Page 28: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/28.jpg)
Diseases associated with Adrenal hormone levels Cushing’s disease
Hyperadrenocorticism widened face with acne and flushing fatty deposits over back of neck stretch marks, easy bruising, hair overgrowth diabetes mellitus muscle loss and fatigue depression and psychosis moon-like face,
Addison’s disease Hypoadrenocorticism
Hyperpigmentation, weight loss
![Page 29: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/29.jpg)
Thyroid Gland
![Page 30: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/30.jpg)
Thyroid Gland
Is located just below the larynx
Secretes T4 & T3 which set BMR & are needed for growth, development
Also secretes Calcitonin which lowers blood calcium levels
![Page 31: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/31.jpg)
Hypothyroidism People with inadequate T4 & T3 levels are
hypothyroid Have low BMR, weight gain, lethargy, cold
intolerance Hyperthyroidism
Autoimmune disease where antibodies act like TSH & stimulate thyroid gland to grow & oversecrete = hyperthyroidism
Characterized by exopthalmos, weight loss, heat intolerance, irritability/anxiety, high BMR, rapid heart rate
Diseases of the Thyroid
![Page 32: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/32.jpg)
Graves’ disease
Graves disease is a form of hyperthyroidism that often presents with exopthalmos
![Page 33: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/33.jpg)
Parathyroid Glands
Are 4 glands embedded in lateral lobes of thyroid gland
Secrete Parathyroid hormone (PTH) Elevates blood Ca2+
levels
![Page 34: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/34.jpg)
Parathyroid Hormone and Calcitonin: Control of Blood Calcium
Two antagonistic hormones, parathyroid hormone (PTH) and calcitonin play the major role in calcium (Ca2+) homeostasis in mammals
CalcitoninThyroid glandreleasescalcitonin.
StimulatesCa2+ depositionin bones
ReducesCa2+ uptakein kidneys
STIMULUS:Rising bloodCa2+ level
Blood Ca2+
level declinesto set point
Homeostasis:Blood Ca2+ level
(about 10 mg/100 mL)
Blood Ca2+
level risesto set point
STIMULUS:Falling bloodCa2+ level
StimulatesCa2+ releasefrom bones
Parathyroidgland
IncreasesCa2+ uptakein intestines
Activevitamin D
Stimulates Ca2+
uptake in kidneys
PTH
![Page 35: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/35.jpg)
PancreasIslets of Langerhans
![Page 36: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/36.jpg)
Islets of Langerhans
Are scattered clusters of endocrine cells in pancreas
Contain alpha & beta cells
![Page 37: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/37.jpg)
Betas secrete insulin in response to low blood glucose Promotes entry of
glucose into cells & conversion of
glucose into glycogen & fat
Decreases blood glucose
Islets of Langerhans continued
![Page 38: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/38.jpg)
Diabetes Mellitus
Diabetes mellitus is the best-known endocrine disorder Is caused by a deficiency of insulin or a decreased
response to insulin in target tissues Is marked by elevated blood glucose levels
Type I diabetes mellitus (insulin-dependent diabetes) Is an autoimmune disorder in which the immune
system destroys the beta cells of the pancreas Type II diabetes mellitus (non-insulin-dependent
diabetes) Is characterized either by a deficiency of insulin
or, more commonly, by reduced responsiveness of target cells due to some change in insulin receptors
![Page 39: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/39.jpg)
Alphas secrete glucagon in response to low blood glucose during periods of fasting Stimulates glycogenolysis & lipolysis Increases blood glucose
Islets of Langerhans continued
![Page 40: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/40.jpg)
Pineal Gland
Is located in basal forebrain near thalamus
Secretes melatonin in response to activity of suprachiasmatic nucleus (SCN) of hypothalamus
![Page 41: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/41.jpg)
Pineal Gland
SCN is primary timing center for circadian rhythms Reset by daily light/dark changes
Melatonin is involved in aligning physiology with sleep/wake cycle & seasons Secreted at night & is inhibited by light Inhibits GnRH (antigonadotropic) in many animals
![Page 42: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/42.jpg)
Gonads: Sex & Reproductive Hormones
Gonads (testes & ovaries) secrete steroid hormones The testes primarily synthesize androgens, the main
one being testosterone Which stimulate the development and maintenance of the
male reproductive system Estrogens, the most important of which is estradiol
Are responsible for the maintenance of the female reproductive system and the development of female secondary sex characteristics
Progestins, which include progesterone Are primarily involved in preparing and maintaining the
uterus in mammals
![Page 43: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/43.jpg)
Testosterone
Testosterone causes an increase in muscle and bone mass and is often taken as a supplement to cause muscle growth
![Page 44: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/44.jpg)
Placenta
Placenta secretes estrogen, progesterone, hCG, and numerous polypeptide hormones
![Page 45: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/45.jpg)
Autocrine & Paracrine Regulation
![Page 46: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/46.jpg)
Autocrine & Paracrine Regulation
Autocrine regulators are produced & act within same tissue of an organ
Paracrine regulators are produced within one tissue & act on different tissue in same organ.
Examples of autocrines & paracrines include: Cytokines (lymphokines, interleukins) Growth factors (promote growth & cell division) Prostaglandins (produced by most organs and have a
wide variety of functions)
![Page 47: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/47.jpg)
Have wide variety of functions Different PGs may exert antagonistic effects in
tissues Some promote smooth muscle contraction &
some relaxation Some promote clotting; some inhibit
Promotes inflammatory process of immune system
Plays role in ovulation Inhibits gastric secretion in digestive system
Prostaglandins (PGs) continued
![Page 48: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/48.jpg)
Cyclooxygenase (COX) 1 & 2 are involved in PG synthesis Are targets of a number of inhibitory non-
steroidal anti-inflammatory drugs (NSAIDs) Aspirin, indomethacin, ibuprofen inhibit both COX
1 & 2 thereby producing side effects Celebrex & Vioxx only inhibit COX 2 & thus have
few side effects
Prostaglandins (PGs) continued
![Page 49: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/49.jpg)
Invertebrates
Invertebrate regulatory systems also involve endocrine and nervous system interactions
Example: Control of Metamorphosis in Insects Brain hormone
Stimulates the release of ecdysone from the prothoracic glands
Ecdysone Promotes molting and the development of adult
characteristics Juvenile hormone
Promotes the retention of larval characteristics
![Page 50: Endocrine Glands Hypothalamus Pineal gland](https://reader033.vdocument.in/reader033/viewer/2022061521/555d10b6d8b42ab2228b48a0/html5/thumbnails/50.jpg)
Control of molting and development in insects
Brain
Neurosecretory cells
Corpus cardiacum
Corpus allatum
EARLYLARVA
LATERLARVA PUPA ADULT
Prothoracicgland
Ecdysone
Brainhormone (BH)
Juvenilehormone(JH)
LowJH
Neurosecretory cells in the brain produce brain hormone (BH), which is stored in the corpora cardiaca (singular, corpus cardiacum) until release.
1
BH signals its main targetorgan, the prothoracicgland, to produce thehormone ecdysone.
2
Ecdysone secretionfrom the prothoracicgland is episodic, witheach release stimulatinga molt.
3
Juvenile hormone (JH), secreted by the corpora allata,determines the result of the molt. At relatively high concen-trations of JH, ecdysone-stimulated molting producesanother larval stage. JH suppresses metamorphosis.But when levels of JH fall below a certain concentration, a pupa forms at the next ecdysone-induced molt. The adultinsect emerges from the pupa.
4